Advanced topologies and modulation strategies for multilevel inverters

Multilevel inverters have been attracting increasing attention in the past few years as power converters of choice in high voltage and high power applications. Various topologies to realize these inverters have been introduced and studied. Waveform synthesis methods for these inverters include staircase modulation, sine-triangle carrier modulation, space vector modulation, and other predictive methods. This paper presents the development of real-time voltage control techniques for multilevel inverters based on multilevel sigma delta modulators. The spectral performance of the output waveforms is investigated. Various design criteria, performance characteristics, comparison with existing modulation methods and other practical issues are discussed in detail in the paper.